1. Field of the Invention
The present invention relates to a vehicle fault determination device. More particularly, to a fault determination method of a relay connected to a power source.
2. Description of Background Art
In a vehicle having an electric actuator, it has been proposed to provide a fail-safe relay between a power source and the electric actuator to positively shut off power in the event of a non-functional condition. Because of its configuration, a relay may become stuck due, for example, to welding of its contact portion. For this reason, a technique has been proposed to determine whether the contact portion is in such a non-functional condition. See, for example, Japanese Patent No. 3097723.
To provide a relay, a signal output is required to control the operation thereof. As a result, a control section needs an output port to control the relay. To determine whether the relay is faulty, an input port is required in addition to the output port. The input port is used to receive a signal that indicates the ON/OFF state of the relay during a fault determination test. The number of ports that can be accommodated in the control section is limited. Increasing the number of dedicated ports restricts the degree of freedom in designing the control section.